(a) Field of the Invention
The present invention relates to a field emitter electrode and a method of manufacturing the same, and more particularly, to a field emitter electrode including carbon nanotubes, and a method of manufacturing the same.
(b) Description of the Related Art
A field emission device has a structure where electrons emitted from a cathode are accelerated in a vacuum to be led to an anode. Examples thereof include lighting generating visible rays by forming a fluorescent material in an anode, and an X-ray tube generating X-rays by forming a metal target.
Performance of the field emission device largely depends on an emitter electrode that is capable of emitting electrons. Recently, a nanomaterial such as carbon nanotubes (CNT) has been frequently used as an electron emission material for the emitter electrode having an excellent electron emission characteristic.
Carbon nanotubes (CNT) have a geometric structure with a low work function and a high aspect ratio, and thus are useful in field emission. That is, when an electric field is applied to the emitter, the electric field is concentrated on the emitter to emit electrons. The carbon nanotubes have a very high field enhancement factor, and thus may easily emit electrons even in a low electric field.
There are various methods of forming the emitter with the carbon nanotubes. Among the methods, screen printing has merits in that its manufacturing cost is low and mass production is easily performed. In a dipping method of applying a small amount of mixture including carbon nanotubes in a paste state on a cathode, a process of forming the paste on a substrate is simple.
In order to use the screen printing or the dipping method, after the carbon nanotube paste is manufactured, the carbon nanotube paste is subjected to low temperature atmospheric firing, surface treatment, and high temperature vacuum heat treatment steps.
However, the carbon nanotubes are bonded to the substrate by only weak force such as van der Waals force. Accordingly, some of the carbon nanotubes are vaporized due to a high temperature in a manufacturing process, thus deteriorating flatness. In addition, the emitter is partially detached under a high current in a high electric field to generate an arc.
When flatness is deteriorated, field emission locally occurs, and accordingly, there are problems in that lifetime is reduced and stability gets worse.